Buckling failure mechanism and critical buckling load prediction method of super-long piles in soft-clay ground in deep water

Abstract

Buckling may be a possible failure mode of super-long piles in soft-clay ground in deep water as concerned by several researchers. Although there are many studies on the failure mode of super-long piles in sands or silts deposits, few studies have been carried out thoroughly on mechanical mechanism of buckling instability in soft-clay ground in deep water and the corresponding calculation method. In this paper, first, the Riks Arc-Length method in ABAQUS was evaluated and verified using the FEM simulation and the analytical results from Bhattacharya. It is observed that buckling failure is indeed one of failure modes of super-long piles in soft-clay ground. And then, the buckling capacities of super-long piles were assessed due to various influential parameters. The results show that the critical buckling load of super-long piles increases with the increase of elastic modulus and embedding rates of piles, and the increase of elastic modulus and cohesion of soil, while decreases with the increase of slenderness ratios of piles and horizontal loads. Finally, a prediction method of the critical buckling load for super-long piles was presented based on the above sensitivity analysis for influential parameters and the Euler buckling formula, and the criterion for buckling instability for super-long piles was proposed as well.